Fix example buildset

We don't want the doxygen dependency for building wayland
Merge pull request #2 from capisce/master

Some fixes to build
Guard for empty shell sessions
Use fork and execlp instead of system

Its just to save one process, but still
Add the builds build and src path to the build_environment.json

The buildsets are not suppose to have them have the arguments persisted,
they do, but that can be fixed later:)
add skip build option
Make it possible to show the command executed by bs

also fix environment variable generation to actually use the build_path
etc.

fix so that the arguments node is deleted for all projects when
buildaction::execute is done
Fix naming of buildshells

The name is the buildDir!!!! yay, but its also possible to add a shorter
name through the bs_name function. This adds also the delimiter flag to
jsonmod since the dot notation isn't well suited for paths.
Support git repos not on a branch in state_git
Fixed deep cleaning of builds (and --skip-build / unsetting of env).